Rotary tool

ABSTRACT

A machining tool for the fine machining of internal surfaces, with a blade carrier and cutting inserts preferably attached releasably thereto. An adjusting device for the precision adjustment of the cutting edge is provided. The blade carrier has at least one slit located closer to the longitudinal axis of the machining tool than is the cutting insert, thus creating a blade carrier segment which can be essentially radially adjusted and which carries the cutting insert and which is connected in one piece with the remaining blade carrier. The degree of freedom of the blade carrier segment permitted by the slit can be stabilized via adjusting device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention on hand relates to a rotary tool, in particular amachining tool for the fine machining of internal surfaces, with a bladecarrier and cutting inserts preferably attached releasably thereto, inparticular indexable inserts according to DIN German Industrial Norm!,whereby an adjusting device for the precision adjustment of the cuttingedge is provided.

2. Discussion of the Background

Today's modern manufacturing technology regards the reduction ofproduction steps from the raw part to the finished product in finemachining quality as an important point for cost optimization and timesavings. High-speed, stable, high-performance spindles create newopportunities for new rotary tool systems. A high degree ofconcentricity of the tool and cylindricity of the machined through-boresis required in particular for the machining of through-bores or blindhole bores, such as for example cylinder head bores. Such toolstherefore frequently use extremely stable cutting inserts.

For this purpose, a rotary tool is known, on whose blade carrier cuttinginserts can be radially aligned by using an adjusting device. Theadjusting device consists of a clamping claw which can be fixed with atension screw on the blade carrier in order to attach the cuttinginsert, which consists for example of hard metal on the blade carrier,and which also consists of an adjusting screw for the radial alignmentof the cutting insert or blade. The clamping claw can hereby be loweredinto the machining space. The cutting inserts have on their top side aground toothing that engages with an identical toothing on the undersideof the clamping claw. The toothing extends parallel to the main blade,so that the toothing of the clamping claw remains engaged with thetoothing of the blade when the blade is shifted radially in order toadjust the diameter. The adjusting screw is arranged at an angle to thetension screw of the clamping claw in a plane parallel to the end faceof the tool and is constructed conically at its tip, so that the conicalflank of the adjusting screw is able to act on the inner, lateralsurface of the blade in order to be able to push the blade radiallyoutward during the adjustment.

But a significant disadvantage of this tool is that specially groundcutting inserts with a correspondingly precision-ground toothing ontheir top must be used. The use of any desired cutting inserts, such asfor example low-cost indexable inserts according to DIN or ISO norms isnot possible with the known tool.

Another disadvantage is that the adjusting screw is only able to exertforces which move the blade radially outward. If, during adjustment ofthe diameter, it is necessary to shift the blade radially inward, thismust be done manually by pressing on the outside, lateral blade surface,creating a significant risk of injury.

In order to be able to fix the blade to the blade carrier, it is alsonecessary that a precision-manufactured clamping claw with toothing onits underside is used. This increases the necessary number of partsrequired for assembling the entire tool. A simple clamping of the bladewith a screw, as this is the case with standard DIN indexable plates, isnot possible with this tool. Care must also be taken that no soilparticles are present in the toothing of the clamping claw or in thetoothing of the blade, since an accurate alignment of the blade isotherwise made harder.

Handling this tool during blade adjustment also causes problems, since,for the adjustment of the blade the tension screw of the clamping clawmust be released from the front while looking at the blade, and theadjusting screw must be driven at an angle from the opposite side. Theconstant, necessary back and forth movement of the tool makes anaccurate, radial adjustment of the cutting inserts more difficult.

Another disadvantage of the known tool is that the adjusting screwsecures the blade only against a radially inward movement. A slipping ofthe blade radially outward is supposed to be prevented by the clampingforce of the clamping claw; but this is not guaranteed.

It is therefore the objective of the invention to create a rotary toolwhich enables both a separation of the two functions of clamping theblade on the one hand and adjustment of the blade on the other hand insuch a manner that even standardized cutting inserts with predefined,tolerance-specific measuring deviations can be used.

This objective is realized with the characteristic features of claim 1.

SUMMARY OF THE INVENTION

The dividing of the blade carrier into the blade carrier itself and intoat least one blade carrier segment carrying the blade enables theseparation of important functions of the blade carrier, i.e. a firstfunction of providing a stable seat for the blade, and a second functionof a radial adjustment of the blade. This makes it possible for thefirst time to tightly fix the blade to the blade carrier without havingto limit the adjusting possibility. By using at least one slit whichseparates the blade carrier from at least one blade carrier segment,whereby the blade carrier segment still remains connected in one piecewith the blade carrier, a new degree of freedom is created, which may beused for adjusting the blade tightly fixed to the blade carrier segment.According to the invention, thus not the cutting insert but rather apart of the blade carrier is adjusted by means of a variation of theslit width.

An adjusting device stabilizes the adjusted cutting edge indirectly bystabilizing the blade carrier segment in relation to the blade carrier.Since the blade carrier and the blade carrier segment remain connectedin one piece with each other, a high number of parts can be avoided fromthe start. In addition, the assembly of attachment screws for the bladecarrier segment is as a principle eliminated, resulting in theadditional advantage that a minimum of parts is placed between blade andblade carrier, which is another benefit for the stability of the tool.

It is also possible that instead of the cutting inserts fixed with ascrew to the blade carrier segment, cutting plates are used which aresoldered into their seat on the blade carrier segment, thus yet againreducing the number of parts. Depending on the specific application, oneor more slits, arranged for example in a star shape, may create one ormore star-shaped blade carrier segments whose additionally obtainedelasticities or degrees of freedom can be uncoupled from each other.

The at least one slit extends in a straight line in a plane which isessentially parallel to the axis of the drilling tool, then at least oneblade carrier segment can be formed which remains connected in the areaof the slit base in one piece with the blade carrier in a plane oppositefrom the tool end face. The blade carrier segment formed in this way nowcan be considered numerically like a freely projecting bending bar andcan thus be easily used in standard calculation methods for determiningloads. Another advantage hereby is that a blade carrier segment formedin such a manner can be easily stabilized and already has a relativelylarge force transfer surface towards the blade carrier, enabling thetransfer of high cutting forces without problems.

The area of the slit base at which the blade carrier remains connectedto the blade carrier segment forms a material joint which remainsbetween the blade carrier segment and the blade carrier and which can bestabilized by means of two opposing force vectors. This makes itpossible to control the tensions in the blade carrier. This can becompared to a freely projecting bending bar, on which a tensile forceacts for example in the outer end area, and which is able to supportitself with a section located further inward on an opposing force. Thissystem is determined statically and remains stationary, so that theblade which in a sense is adjusted by the two opposing force vectors ispermanently stabilized. The direction of action of the force vectorsacting in opposing direction to each other can hereby be reversed. It isadvantageous that with known material constants all forces occurring inthe tool can hereby be calculated, such as for example thrust, tensile,shear, and transverse forces, so that a numerical simulation can be usedfor the tool for the purpose of optimization.

In another embodiment, if the adjusting device has at least oneadjusting element and one fixing element, then the user can clearlydetermine which means are to be used to adjust the blade radially andwhich means are to be used to fix the adjusted blade in its position.The adjusting element can hereby be associated with one force vector,and the fixing element with the other force vector.

In still another embodiment, the adjusting device is formed by a pair ofparallel and axially stacked control elements whose axes extendpreferably vertically to the slit. In this way it is possible toassociate each of the opposing force vectors with a control element. Thecontrol elements enable a very fine and accurate radial adjustment ofthe blade fixed to the blade carrier segment. Access to the controlelements is possible, in relation to the cutting edge, from two sides,whereby the function may remain the same on both sides. With acorresponding design, access to the control elements for their operationcan be provided for example from the front, with a view towards thecutting insert, enabling a permanent optical or metrological control ofthe adjustment process, so that an extremely precise adjustment of thecutting insert can be performed in the μ-range.

If the control elements according to another embodiment are formed byscrew/nut tension devices, this results in a particularly space-savingdesign which, with a corresponding selection of the threads, may resultin an extremely fine reduction, so that adjustments of the cuttinginsert which are accurate in the μ-range can be relatively easilyrealized. Depending on the choice of the thread direction, a movement ofthe blade carrier segment and thus of the cutting insert into the plusrange, i.e. an increase in diameter, is performed for example in case ofa rotation to the right, regardless of the fact whether access to thecontrol elements is provided from the front or the back. In the case ofa rotation to the left, the reverse happens, i.e. the diameter becomessmaller. Since both control elements are always kept under tension, itis ensured that the adjusted position of the cutting insert ismaintained and is not adjusted in the insert during the machining ofworkpieces. The clamping devices can hereby be constructed in such asize that the weakening of the blade carrier through the slit is largelycompensated.

In still a further embodiment, the screw/nut tension devices areconstructed in accordance with the differential thread principle. Thisoffers the advantage that a relatively high output force can be achievedwith a relatively small drive force which can be exerted manually, forexample.

In another embodiment, the screw/nut tension devices are formed in twoparts of a setscrew and a threaded jacket. This advantageously enables asimple and cost-efficient use of standard commercial setscrews andthreaded jackets. Depending on tool geometry and the width of the slit,this variation easily allows an adjusting range of at least ±0.2 mm,i.e. a radial shift of at least ±0.1 mm and more per cutting insert.

In still another embodiment, the screw/nut tension device is formed intwo parts from a stepped setscrew and a threaded jacket. The advantageof this Variation II over the Variation I discussed in the embodimentabove is mainly that the production and assembly of the adjusting devicefor adjusting the blades can be simplified even more. For theproduction, a continuous thread G1' in the blade carrier and in theblade carrier segment which is separated from the blade carrier by theslit is sufficient. The preassembled screw/nut tension unit consistingof the stepped setscrew with a larger thread G1 and a smaller thread G2,as well as a threaded jacket having an internal thread of the type G2and an external thread G1, is inserted into such a threadedthrough-bore. This preassembly is installed in a state where thethreaded jacket is screwed with a certain axial residual play onto thesmaller thread G2 of the stepped screw. In this preassembled state, thispreassembly can be screwed into the threaded through-bore of the tool,initially until one of the components strikes the internal thread whichis reached later. By means of a relative rotation between the threadedjacket and the stepped setscrew, the later arriving external threadsection is now synchronized with the internal thread, whereupon bothelements (threaded jacket, stepped setscrew) are preferably rotated,synchronized in the threaded bore by using suitable tools (hexagonsocket screw key) until the suitable end position (without force) of thepreassembly in the threaded bore is reached.

The special part here is that now regardless of which part of thepreassembly is driven, the other part is automatically kept stationaryby the higher friction moment (larger thread diameter), so that thedriven part is turned relative to the stationary part. Due to thedifference in pitches between thread sections G1 and G2 (the analogapplies here to the thread sections G1 and G2 according to Variation Ialso), the rotary drive movement of one part results in a relativemovement of the sections of the blade carrier segment separated by theslit. When providing a right thread on sections G1 and G2, the clockwiserotation of the components results in a pushing away of the sections ofthe blade carrier segment separated by the slit; in case of acounter-clockwise rotary drive movement, an approaching, i.e. attractingmovement, takes place. In this manner the diameter on which the bladesare located can not only be moved to the positive, but can also bepushed in the opposite direction, i.e. inward. A tool with whichdiameter adjustments in the range of 0.3 mm can be achieved has alreadybeen practically realized.

Another advantage of this Variation II is that the adjustment of theblade is possible from both sides of the screw/nut tension device. Thismakes it possible to observe the blade which is being adjusted from theside at which the adjusting tool is being applied.

In still a further embodiment, if two slits are provided, so that theblade carrier segment is connected in one piece with the blade carrierby means of a material bridge remaining between the two slits, thisadvantageously results in an adjustment of the blade carrier segmentwhich carries the blade in the manner of a swing or seesaw. This seesawcan be supported on both sides or on one side of the material bridgeonly, and thus can be made stationary. This results in two basicsystems, whereby one can be compared to a centrally supported bendingbar at whose both end sections tensile or thrust forces act, and theother to a centrally supported bending bar at whose one end tensile andthrust forces act. These two basic systems again are determinedstatically and remain stationary, so that in a corresponding sense theblade adjusted by means of the two opposing force vectors is permanentlystabilized. The direction of action of the opposing force vectors canhereby be reversed. It is advantageous that, with known materialconstants, all forces occurring in the tool can hereby be calculated,such as for example thrust, tensile, shear, and transverse forces, sothat a numerical simulation can be used for the tool for the purpose ofoptimization.

In another embodiment, both slits are located at least partially in amutual plane, whereby each slit is associated with an adjusting device.The advantageous arrangement of the lines of action of the opposingforce vectors on both sides of the material bridge results in a kind ofswing or seesaw. This seesaw can be brought to rest by support on bothsides of the material bridge, i.e. the blade carrier segment with theblade insert can be very precisely adjusted and stabilized with it.

In still another embodiment, the material bridge has a cross-sectionsurface, the largest extension of which is oriented in peripheraldirection. This advantageously ensures that the resistance against abending of the material bridge around a radially oriented axis issignificantly smaller than that around an axis oriented in thelongitudinal axis of the tool. The cross-section is hereby oriented sothat the main cutting forces on the blade extend essentially parallel tothe larger extension of the cross-section, i.e. in the peripheraldirection.

Other advantageous embodiments of the subject of the invention are alsoclaimed.

The force translation can be adapted advantageously to the remainingmaterial bridge by means of the difference in thread pitches. Theposition of the material bridge is preferably such that the main cuttingforces are introduced at a favorable point from the blade via the bladecarrier segment into the blade carrier.

A main area of application of this invention is the field of tools usingso-called DIN or ISO indexable inserts which are regularly manufacturedwith a certain tolerance range, so that the desired accuraciesfrequently cannot be adjusted without further measures. Anotheradvantage of the invention is also that this technology is suitable fortools with soldered-in blades which are retrofitted to the functionprinciple.

A possible embodiment of the tool according to the invention isexplained in more detail below in reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a three-dimensional, schematically simplified view of thetool according to the invention;

FIG. 2 shows a lateral view of a first embodiment of the tool accordingto the invention with a cut-away;

FIG. 3 shows a frontal view of the first embodiment of the toolaccording to the invention with a cut-away;

FIG. 4 shows a frontal view of a second embodiment of the tool accordingto the invention with a break-away;

FIG. 5 shows a lateral view of the second embodiment of the toolaccording to the invention;

FIG. 6 shows a schematic flow-chart during the partial assembly of thetool according to the invention;

FIG. 7 shows a three-dimensional, schematically simplified view of thetool according to the invention in which a single slit is shown; and

FIG. 8 shows a three-dimensional, schematically simplified view of thetool according to the invention in which multiple single slits areshown.

In the figures, identical reference numbers have been used for parts ofdifferent embodiments which correspond functionally.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a simplified view of an embodiment of the tool 1 accordingto the invention. Two cutting inserts 4 are arranged on the bladecarrier 2. An adjusting device 6 is used for the radial fine adjustmentof the cutting edge 8 of the cutting inserts 4. The adjusting device 6consists of an adjusting element which can be either of 6a or 6b, and afixing element which is the other. The blade carrier 2 has slits 10which separate two blade carrier segments 12 from the blade carrier 2.Each of the blade carrier segments 12 carries a cutting insert 4 and isconnected in a radially adjustable manner and in one piece with theblade carrier 2 by way of a material joint 14. The cutting inserts 4 arefixed by means of screws 16 to the respective blade carrier segment 12.The slits 10 in part extend straight in a plane which is essentiallyparallel to the axis of the tool 1. The chucking groove 18 is providedwith threaded bores 20 intended for holding the screw/nut tensiondevices 22.

FIG. 2 shows the lateral view of the first embodiment. The chuckinggroove 18 in the blade carrier 2 holds threaded bores 20 into which athreaded jacket 24 is screwed. A setscrew 26 is screwed into a threadedbore 28 in the blade carrier segment 12. The threaded bore 20 with thethreaded jacket 24 and the threaded bore 28 with the setscrew 26cooperate and form the screw/nut tension device 22, whereby the setscrew26 bridges over the slit 10. In this embodiment, the adjusting device 6consists of two screw/nut tension devices 22. One screw/nut tensiondevice 22 acts as the adjusting element which can be either of 6a or 6b,the other screw/nut tension device 22 acts as the fixing element whichis the other of 6a or 6b.

FIG. 3 shows the frontal view of the first embodiment. The parallelslits 10 extending vertically to the viewing plane in the direction ofthe longitudinal axis of the tool partially separate the blade carriersegments 12 from the blade carrier 2. Two radially opposing cuttinginserts 4 are inserted into the radially opposing blade carrier segments12 and are fixed with the screw 16. The setscrew 26 bridges over theslit 10 and engages with the threaded jacket 24, which comprises eitherthe fixing element 6b, or the adjusting element 6b of the adjustingdevice 6, for a radial adjustment of the cutting insert 4. The threadedbore 20 is arranged so as to approximately align with the threaded bore28 or be concentric to it, whereby the threaded bores are aligned in aplane parallel to the end face of the tool 1 approximately vertically tothe slit 10.

FIG. 4 shows the frontal view of a second embodiment. The parallel slits10 which extend vertically to the viewing plane in the direction of thelongitudinal axis of the tool partially separate the blade carriersegments 12 from the blade carrier 2. Two radially opposing cuttinginserts 4 are inserted into the radially opposing blade carrier segments12 and are fixed with the screw 16. The stepped setscrew 36 bridges overthe slit 10 and engages with the threaded jacket 34, which compriseseither the fixing element 6b or the adjusting element 6b of theadjusting device 6, for a radial adjustment of the cutting insert 4. Thethreaded bore 30 is arranged so as to approximately align with thethreaded bore 38 or be concentric to it, whereby the threaded bores arealigned in a plane parallel to the end face of the tool 1 approximatelyvertically to the slit 10 and are constructed as a through-bore havingthe same thread.

FIG. 5 shows a simplified lateral view of the second embodiment. TheChucking groove 18 in the blade carrier 2 holds threaded bores 30 intowhich the threaded jacket 34, which is not shown here in detail, isscrewed. The setscrew 36, which is not shown here, is screwed into athreaded bore 38 in the blade carrier segment 12. The threaded bore 30with threaded jacket 34 and the threaded bore 38 with the steppedsetscrew 36 cooperate and form the screw/nut device 32, whereby thestepped setscrew 36 bridges over the slit 10, to form the fixingelement, which can be either 6a or 6b, or the adjusting element, whichis the other of 6a or 6b, of the adjusting device 6, the construction ofwhich is not shown. The threaded bore 30 and the threaded bore 38 havethe same thread and are constructed so as to align with each other as athreaded through-bore.

FIG. 6 shows a flow chart for the partial assembly of the secondembodiment of tool 1. In the first step, the stepped setscrew 36 isscrewed into the threaded jacket 34, preferably with a certain residualplay of the thread engagement. The resulting pair consisting of athreaded jacket and a stepped setscrew is screwed into and through thethreaded bore 38 in the blade carrier segment until the threaded jacket34 reaches the slit 10. By working from the opposite side through thethreaded bore 30, the threaded jacket 34 is now turned further by itselfuntil it engages with the threaded bore 30. The pair consisting of thestepped setscrew 36 and the threaded jacket 34 now can be moved fromboth sides further together in axial direction in the threadedthrough-bore formed by threaded bores 30 and 38 until the steppedsetscrew 36 bridges in a final position over the slit 10 and thethreaded jacket 34 is positioned in the blade carrier 2 in its finalposition in the threaded bore 30.

As a result of the previously described assembly, the assembled unit ofthreaded jacket and stepped setscrew is in the inserted state at anydesired location in a forceless state. This forceless state can beachieved regardless of the overlapping length Su over which the steppedthreaded section is functionally engaged with the internal thread of thethreaded jacket.

As can be best seen from the detail view according to FIG. 6, theadjusting element, which can be either 6a or 6b, and the fixing element,which is the other, assembled in this manner have the advantage that theadjusting device 6 is always operated without problems, even if therespective tool for driving the adjusting device is used from one orfrom the other side. If according to the detail view of FIG. 6 a tool,such as for example a hexagon socket screw key, is inserted from thebottom into the stepped setscrew and the later is rotated, the threadedjacket in part 2 nevertheless remains stationary, since the frictionmoment is lower in the part of the thread with the smaller diameter thanit is in the part of the larger thread diameter on the threaded jacket.The width of the slit 10 is thus changed reliably in a specificdirection.

If reversely a tool is applied from the other side, i.e. according tothe detail view of FIG. 6, from the top, the threaded jacket is firstbrought to rotate and then moves on the smaller thread of the steppedsetscrew 36. The setscrew 36 does not rotate along, since the frictionforces between threaded jacket and smaller thread of the steppedsetscrew 36 act on a smaller radius than the thread support force in thehead of the stepped setscrew 36. Another special advantage is that anidentical rotation direction of the applied tool brings about anadjustment of the blade in the same adjusting direction, regardless ofwhich side the tool is applied to.

Changes from the described embodiments are naturally possible withoutleaving the basic concept of the invention behind. The invention offerspossibilities of varying the arrangement, position, and size, but alsothe number of slits within wide limits. A suitable ratio between bladecarrier cross-section and blade carrier segment cross-section is chosendepending on the application area of the tool. And finally, the slitwidth is also influenced by the chosen process for producing the slit.An advantageous method for this is the wire erosion process, which makesit possible to produce a slit with a suitable width already in a singlestep by the choice of tool.

The expansion joint or the material joint subject to elastic deformationbetween blade carrier segment and blade carrier can also be varied,whereby preferably the orientation of the main cutting force is beingtaken into account. FIG. 1 schematically illustrates the ratios for anorientation of the main cutting force in a radial plane of the tool. Itcan be seen that the cross-section surface (striated) of the expansionjoint is oriented essentially parallel to the main cutting force HSK.

In this way the invention creates a rotary tool 1, in particular amachining tool 1 for the fine machining of internal surfaces, with ablade carrier 2 and cutting inserts 4 preferably attached releasablythereto, in particular indexable inserts according to DIN GermanIndustrial Norm!, whereby an adjusting device 6 for the precisionadjustment of the cutting edge 8 is provided, wherein the blade carrier2 has at least one slit 10 radially inside the cutting insert 4, thuscreating a blade carrier segment 12 which can be essentially radiallyadjusted and which carries the cutting insert 4 and which is connectedin one piece with the remaining blade carrier 2, whereby the degree offreedom of the blade carrier segment 12 permitted by the slit 10 can bestabilized via adjusting device 6.

FIG. 7 shows another embodiment of the invention wherein a single slit10 is used instead of the two slits of the previous embodiment, and inwhich there is also shown the location of a material joint 13 whichconnects the blade carrier segment 12 to the blade carrier 2. FIG. 8shows the basic embodiment of the invention as shown in FIG. 7, butincludes multiple single slits 10, 10. The reference numeraldesignations shown in FIGS. 7 and 8 designate features of the inventionthat are the same as the features as previously discussed for the twoslit embodiment of the invention; as such, a listing of the featureswill not be repeated. Additionally, FIGS. 3 and 4 depict a front view ofthe tool 1 with a cut-away that correctly depicts the front view of thesingle slit embodiment shown in FIG. 8.

The operation of the single slit embodiment is similar to the two slitembodiment discussed earlier. The blade carrier segment 12 is stabilizedby an adjusting device 6. In one embodiment the adjusting device 6includes an adjusting element which can be either 6a or 6b, and a fixingelement which is the other. The adjusting element which can be either 6aor 6b or the fixing element of 6a or 6b which is the other may belocated near the tool 1 tip and the other of the adjusting element 6a or6b or the fixing element the other of 6a or 6b may be located furtherfrom the tool 1 tip. The adjusting or fixing element, one of 6a or 6b,located nearest the tool 1 tip is placed in compression in order to movethe cutting edge 8 to a larger cutting diameter. The other of theadjusting or fixing element, the other of 6a or 6b, located furthestfrom the tool 1 tip is placed in tension so as to stabilize and securethe position of the cutting edge 8.

The tension of the adjusting/fixing elements 6a, 6b can be reversed soas to locate the cutting edge 8 at a diameter which is smaller than thecutting edge diameter void of adjusting device forces.

The adjusting device 6 of this single slit embodiment, as does the twoslit embodiment, can take the form of a pair of parallel and axiallystacked control elements comprising the adjusting/fixing elements 6a,6b, screw/nut tension devices 22 in conjunction with a threaded bore 20,screw/nut devices 22 constructed in accordance with the differentialthread principle, screw/nut devices 22 having a setscrew 26 at one endof which is threaded into the blade carrier segment 12 and an other endthreaded into a threaded jacket 24 which is in turn threaded into theblade carrier bore 20, and an adjusting device similar to the previousone except that the setscrew 36 is stepped and the threaded jacket 34 isthreaded on the smaller diameter end of the setscrew 36. The operationof each is evident from the previous description and will not bediscussed here.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A rotary tool, comprising:a blade carrier; atleast one slit extending in said blade carrier in a straight line in aplane which is substantially parallel to a longitudinal axis of therotary tool, thereby creating a blade carrier segment connected to aremainder of said blade carrier by a material joint; a cutting insertmounted to said blade carrier segment such that said at least one slitis located closer to the longitudinal axis of the rotary tool than isthe at least one cutting insert; and an adjusting device comprisingmeans for creating a first force vector and a second force vector whichhave opposing vector directions, the first force vector and the secondforce vector being substantially perpendicular to the at least one slit,said adjusting device partially located in both of said blade carrierand said blade carrier segment for radially positioning the cuttinginsert.
 2. A machine tool for the fine machining of internal surfaces,comprising:a blade carrier; at least one slit extending in said bladecarrier in a straight line in a plane which is substantially parallel toa longitudinal axis of the machine tool, thereby creating a bladecarrier segment connected to a remainder of said blade carrier by amaterial joint; a cutting insert mounted to said blade carrier segmentsuch that said at least one slit is located closer to the longitudinalaxis of the machine tool than is the at least one cutting insert; and anadjusting device comprising means for creating a first force vector anda second force vector which have opposing vector directions, the firstforce vector and the second force vector being substantiallyperpendicular to the at least one slit, said adjusting device partiallylocated in both of said blade carrier and said blade carrier segment forradially positioning the cutting insert.
 3. A rotary tool as recited inclaim 1, wherein the adjusting device has at least an adjusting elementand a fixing element.
 4. A rotary tool as recited in claim 3, whereinthe adjusting device is formed by a pair of parallel and axially stackedcontrol elements having axes which extend vertically to the slit.
 5. Arotary tool as recited in claim 4, wherein the control elements comprisescrew/nut tension devices.
 6. A rotary tool as recited in claim 5,wherein the screw/nut tension devices are constructed in accordance withthe differential thread principle.
 7. A rotary tool as recited in claim6, wherein the blade carrier has bores each containing an internalthread, and the blade carrier segment has bores each containing aninternal thread, and each of the screw/nut tension devices has asetscrew having a first thread pitch engaged in the correspondinginternal thread of the bore located in the blade carrier segment, and athreaded jacket having an internal thread with the same pitch as thesetscrew and an external thread of a different pitch than the setscrewengaged with a corresponding internal thread of the blade carrier bore,and each threaded jacket internal thread engaged with each respectivesetscrew for adjusting the blade carrier segments.
 8. A rotary tool asrecited in claim 6, wherein the blade carrier has bores each containingan internal thread, the blade carrier segment has bores each containingan internal thread, the pitch of the blade carrier internal thread andthe pitch of the blade carrier segment internal thread are substantiallythe same, each blade carrier bore axis is substantially aligned with arespective blade carrier segment bore axis collinearly, and each of thescrew/nut tension devices has a stepped setscrew having a first externalthread and a second external thread which engages said first externalthread with a corresponding threaded bore in the blade carrier segment,said second external thread having a different pitch which has a smallerdiameter than that of said first external thread and bridges the slit,and a threaded jacket having an internal thread and an external thread,the internal thread of the threaded jacket engaging the correspondingsecond external thread of the stepped setscrew, the external thread ofthe threaded jacket engaging the corresponding internal thread of theblade carrier.
 9. A rotary tool as recited in claim 1, wherein therotary tool has a chucking groove located on a recessed portion of theblade carrier adjacent to the blade carrier segment and, the at leastone slit extends essentially in the plane of the chucking groove.
 10. Arotary tool, comprising:a blade carrier; two slits extending in saidblade carrier in a straight line in a plane which is substantiallyparallel to a longitudinal axis of the rotary tool, thereby creating ablade carrier segment connected in one piece with a remainder of saidblade carrier by a material bridge remaining between the two slits; acutting insert mounted to said blade carrier segment such that said atleast one slit is located closer to the longitudinal axis of the rotarytool than is the at least one cutting insert; and an adjusting devicecomprising means for creating a first force vector and a second forcevector which have opposing vector directions acting through the at leastone slit so as to stabilize and position said blade carrier segment tosaid blade carrier, the first force vector and the second force vectorbeing substantially perpendicular to the at least one slit, saidadjusting device partially located in both of said blade carrier andsaid blade carrier segment, said adjusting device having at least anadjusting element and a fixing element.
 11. A rotary tool as recited inclaim 10, wherein the adjusting device is formed by a pair of paralleland axially stacked control elements having axes which extend verticallyto the slit.
 12. A rotary tool as recited in claim 11, wherein thecontrol elements comprise screw/nut tension devices.
 13. A rotary toolas recited in claim 12, wherein the screw/nut tension devices areconstructed in accordance with the differential thread principle.
 14. Arotary tool as recited in claim 13, wherein the blade carrier has boreseach containing an internal thread, and the blade carrier segment hasbores each containing an internal thread, and each of the screw/nuttension devices has a setscrew having a first thread pitch engaged inthe corresponding internal thread of the bore located in the bladecarrier segment, and a threaded jacket having an internal thread withthe same pitch as the setscrew and an external thread of a differentpitch than the setscrew engaged with a corresponding internal thread ofthe blade carrier bore, and each threaded jacket internal thread engagedwith each respective setscrew for adjusting the blade carrier segments.15. A rotary tool as recited in claim 13, wherein the blade carrier hasbores each containing an internal thread, the blade carrier segment hasbores each containing an internal thread, the pitch of the blade carrierinternal thread and the pitch of the blade carrier segment internalthread are substantially the same, each blade carrier bore axis issubstantially aligned with a respective blade carrier segment bore axiscollinearly, and each of the screw/nut tension devices has a steppedsetscrew having a first external thread and a second external threadwhich engages said first external thread with a corresponding threadedbore in the blade carrier segment, said second external thread having adifferent pitch which has a smaller diameter than that of said firstexternal thread and bridges the slit, and a threaded jacket having aninternal thread and an external thread, the internal thread of thethreaded jacket engaging the corresponding second external thread of thestepped setscrew, the external thread of the threaded jacket engagingthe corresponding internal thread of the blade carrier.
 16. A rotarytool as recited in one of claims 10 to 15 wherein the two slits are atleast partially located in a mutual plane, so that the slit farthestfrom the rotary tool tip is associated with the adjusting element or thefixing element of the adjusting device, and the slit closest to therotary tool tip is associated with the fixing element or the adjustingelement of the adjusting device.
 17. A rotary tool as recited in one ofclaims 10 to 15, wherein the material bridge has a cross-sectionalsurface having a largest extension oriented in a peripheral directionsubstantially perpendicular to the longitudinal axis of the rotary tool.18. A rotary tool as recited in one of claims 10 to 15, wherein an axialwidth of the material bridge is adapted to forces exerted with theadjusting device.
 19. A rotary tool as recited in one of claims 10 to15, wherein the cross-section surface of the material bridge is adaptedto the cutting forces which must be introduced into the blade carrier.